1. Field
An aspect of the present disclosure relates to an electronic device and, more particularly, to a semiconductor device having a three-dimensional structure and a manufacturing method thereof.
2. Description of the Related Art
Nonvolatile memory devices are memory devices which retain stored data even when a power supply to the device is cut off. Recently, as further improvements in the degree of integration of two-dimensional nonvolatile memory devices in which memory cells are formed in a single layer over a silicon substrate have become very difficult, there has been proposed a three-dimensional nonvolatile memory device in which memory cells are vertically stacked on a silicon substrate.
Generally, a structure of a three-dimensional nonvolatile memory device includes a plurality of conductive layers and insulating layers which are alternately stacked on a silicon substrate to form multiple, stacked layers of memory cells. Generally, as the height of a stack structure increases so does also the degree of integration of the memory device. However, as the height of the stack structure increases, the stress applied to the stack structure also increases. Accordingly, as a result of the stress, the geometry of the stack structure may change. Therefore, performance of three dimensional memory devices may suffer as the height of the stack structure increases.